How to use the CSS Validator

The simplest way to check a document is to use the basic interface. In this page
you will find three forms corresponding to three possibilities:

Validation by URL

Simply enter the URL of the document you want to validate.
This document can be HTML or CSS one.

Validation by file upload

This solution allows you to upload and check a local file. Click the
"Browse..." button and select the file you want to check.

In this case, only CSS documents are allowed. It means that you
cannot upload (X)HTML documents. You also must be careful with
@import rules since they will be followed only if they explicitely
reference a public URL (so, forget relative paths with this solution)

Validation by direct input

This method is perfect for testing CSS fragments. You just have to
write your CSS in the textarea

The same comments as before apply. Note that this solution is
very convenient if you have a problem and need some help from the community.
It's also very useful to report a bug, since you can link to the resulting
URL to give a test case.

What does the basic validation do?

When using the basic interface, the validator will check the compliance
against CSS 2.1, which is the current
CSS technical recommendation.
It will produce an XHTML output without any warning (you will only see
errors).
The medium is set to "all", which is the medium suitable for all devices
(see
http://www.w3.org/TR/CSS2/media.html for a complete description of
media).

Advanced validation

If you need a more specific check, you can use the advanced interface which
allows to specify three parameters. Here is a little help on each of these
parameters.

Warnings

This parameter is useful to tune the verbosity of the CSS Validator. Indeed,
The validator can give you two types of messages: errors and warnings.
Errors are given when the checked CSS does not respect the CSS
recommendation. Warnings are different from errors since they do not state a
problem regarding the specification. They are here to warn (!) the CSS
developper that some points might be dangerous and could lead to a strange
behaviour on some user agents.

A typical warning concerns font-family: if you do not provide a generic font,
you will get a warning saying that you should add one at the end of the rule,
otherwise a user agent that doesn't know any of the other fonts will switch
to it's default one, which may result in strange display.

Profile

The CSS validator can check different CSS profiles. A profile lists all the
features that an implementation on a particular platform is expected to
implement. This definition is taken from
the CSS site
. The default choice corresponds to the current most used one:
CSS 2.

Medium

Experts Only

Validation Request Format

Below is a table of the parameters you can use to send a query to the W3C
CSS Validator.

If you want to use W3C's public validation server, use the parameters
below in conjunction with the following base URI:http://jigsaw.w3.org/css-validator/validator
replace with the address of your own server if you want to call a private
instance of the validator.

Note: If you wish to call the validator programmatically
for a batch of documents, please make sure that your script will
sleep for at least 1 second between requests.
The CSS Validation service is a free, public service for all, your respect is
appreciated. thanks.

Parameter

Description

Default value

uri

The URL of
the document to validate. CSS and HTML documents are allowed.